Power conversion device and electric vehicle using same

Abstract

A main circuit connection part of a power conversion device (100) comprises: a first conductor (11) provided on the rear surface of a circuit board (80); a second conductor (12) provided on the front surface of the circuit board (80), at least a part of which is opposite the first conductor (11) with the circuit board (80) interposed therebetween, and in which a current flows in a direction opposite to the first conductor (11); a third conductor (13) which is provided on the rear surface of the circuit board (80) while maintaining an insulation distance (D) from the first conductor (11), and in which a current flows in the same direction as the second conductor (12); a fourth conductor (17) provided on the side walls of at least one through-hole (80a) formed in the circuit board (80) and connecting the second conductor (12) and the third conductor (13); a relay part (18a) filling the through-hole (80a) with a member having thermal conductivity; and a cooling part (16) provided on surfaces of the first conductor (11) and the third conductor (13) with an insulating heat transfer material (15) interposed therebetween.

Description

Power conversion device and electric vehicle using the same

[0001] The present application relates to a power conversion device and an electric vehicle using the same.

[0002] Power conversion devices used in electric vehicles such as hybrid cars and electric vehicles are becoming increasingly larger in current and voltage to achieve smaller size and higher efficiency. From the perspective of power module protection, low-inductance technology for main circuit wiring is essential to minimize surge voltages generated during switching. A method for reducing inductance by arranging conductors carrying opposite currents facing each other is already widely known. For example, Patent Document 1 (JP-A-2003-125666) shows that inductance can also be reduced by wiring (patterns) using circuit boards.

[0003] JP 2017-220961 A (paragraph 0009, FIG. 6)

[0004] However, further reduction in inductance requires shortening the distance between opposing wiring (P line / N line) and widening the pattern width, which are limited by structural and manufacturing constraints. In addition, the main circuit wiring, which carries a large current, needs to prevent the temperature rise caused by its own heat generation from being transmitted to components with low heat resistance, so it is also required to have a structure that can be cooled.

[0005] The present application has been made to solve the above-mentioned problems, and has an object to provide a power conversion device that is inexpensive, easy to manufacture, and has high heat dissipation performance, and an electric vehicle using the same.

[0006] The power conversion device disclosed in the present application is characterized by comprising: a first conductor provided on a first surface of a substrate; a second conductor provided on a second surface of the substrate, at least a portion of which faces the first conductor via the substrate, and through which a current flows in the opposite direction to that of the first conductor; a third conductor provided on the first surface of the substrate at an insulating distance from the first conductor, and through which a current flows in the same direction as that of the second conductor; a fourth conductor provided on a side wall of at least one or more through holes formed in the substrate, and connecting the second conductor and the third conductor; and a cooling section provided on each surface of the first conductor and the third conductor via an insulating heat transfer material.

[0007] According to the present invention, by arranging the first conductor opposite the second conductor and adjacent to the third conductor, it is possible to reduce inductance not only in the opposing portions but also in the adjacent portions. Furthermore, it is possible to cool not only the conductor on the underside of the board but also the conductor on the board surface via the conductor on the side wall of the through hole and the relay portion, which makes it possible to miniaturize the power conversion device.

[0008] FIG. 7A is a block diagram showing the configuration of a power conversion device according to embodiment 1. FIG. 7B is a schematic perspective view showing the configuration of a main circuit connection section of the power conversion device according to embodiment 1. FIG. 7C is a cross-sectional view showing the configuration of a main circuit connection section of the power conversion device according to embodiment 1. FIG. 7D is a schematic perspective view showing the configuration of a main circuit connection section of the power conversion device according to embodiment 2. FIG. 7E is a cross-sectional view showing the configuration of a main circuit connection section of the power conversion device according to embodiment 2. FIG. 7F is a cross-sectional view showing the configuration of a main circuit connection section of the power conversion device according to embodiment 3. FIG. 7A and FIG. 7B are cross-sectional views showing the configuration of a main circuit connection section of a power conversion device according to embodiment 4. FIG. 7C is a cross-sectional view showing the configuration of a main circuit connection section of a power conversion device according to embodiment 5. FIG. 7D is a cross-sectional view showing another configuration of the main circuit connection section of the power conversion device according to embodiment 5. FIG. 7E is a diagram showing the configuration of an electric vehicle using a power conversion device according to embodiment 6.

[0009] First Embodiment Fig. 1 is a block diagram showing the configuration of a power conversion device 100 according to a first embodiment of the present invention. As shown in Fig. 1, the power conversion device 100 is composed of a housing 1, a cooler 2, a power module 3, a capacitor 4, a control board 5, an AC output unit 6, and a DC input unit 7. The cooler 2 dissipates heat from heat-generating components, such as the power module, the capacitor, the AC output unit, and the DC input unit, to the outside of the power conversion device.

[0010] Fig. 2 is a schematic perspective view showing the configuration of a main circuit connection section of the power conversion device 100 according to the first embodiment, and is a diagram showing the configuration of the main circuit connection sections between the power module and the capacitor, between the power module and the AC output section, between the power module and the DC input section, and between the DC input section and the capacitor of the power conversion device 100 of Fig. 1. Fig. 3 is a cross-sectional view taken along the line AA in Fig. 2. The main circuit wiring section is used to insert high-voltage wiring from the DC input section to the capacitor, from the capacitor to the power module, and from the DC input section to the power module section.

[0011] As shown in Figures 2 and 3, the main circuit wiring portion in the first embodiment is configured such that the circuit board 80 sandwiches the base material 14 between the first conductor 11 and the second conductor 12. The first conductor 11 and the second conductor 12 are both made of metal and are formed from a material with excellent electrical and thermal conductivity, such as copper or aluminum. In this embodiment, copper is used. The base material 14 is an insulating resin.

[0012] The circuit board 80 has a multi-layer structure and includes not only a copper pattern such as the first conductor 11 but also electronic components (not shown) (components other than the main circuit wiring are not shown).

[0013] In FIG. 2, for example, the current flows in the X direction in the first conductor 11 and in the −X direction in the second conductor 12, so that the current flows in opposite directions (the opposite may also be true).

[0014] The third conductor 13 has the same potential phase (band) as the second conductor 12, and is arranged on the back surface, which is the first surface of the circuit board 80, which is a different layer from the second conductor 12, via a relay portion 18a and a substrate 14 provided in a through hole 80a formed in the circuit board 80. The relay portion 18a is formed of a material with excellent thermal conductivity. The third conductor 13 is arranged on the same plane as the first conductor 11 and extends on the circuit board 80 while maintaining an insulation distance D from the first conductor 11. At least one through hole 80a is formed in the circuit board 80.

[0015] An insulating heat transfer material 15 is installed between the cooling unit 16 and the first conductor 11. The insulating heat transfer material 15 has an insulating function and a heat dissipation function between the first conductor 11 and the third conductor 13 and the cooling unit 16. The insulating heat transfer material 15 is in contact with some or all of the first conductor 11 and the third conductor 13, and is configured to be able to dissipate heat to the cooling unit 16 in areas where heat dissipation is required.

[0016] The first conductor 11, the third conductor 13, and the fourth conductor 17 formed on the side wall of the through hole 80a are composed of separate parts and are electrically connected when the circuit board 80 is molded. Unlike when a molded bus bar is used, the first conductor 11 and the second conductor 12 form parallel plates with a relatively thin substrate 14 sandwiched between them, allowing for a shorter distance between the electrodes than with a molded bus bar, which has the effect of reducing inductance. Furthermore, because the first conductor 11 and the third conductor 13 are arranged on the same plane, they also form parallel plates at the side surfaces, which is expected to further reduce inductance.

[0017] In Patent Document 1, the main circuit is only cooled on one side, and the side opposite the cooled side dissipates heat through the substrate and cooling conductor, but is not actively cooled, and the top surface remains at a high temperature. However, in this application, the main circuit on the top layer is also configured to dissipate heat to the cooling part with high conductivity through relay part 18a and fourth conductor 17.

[0018] When better cooling performance is required, using metal for relay portion 18a makes it possible to transfer heat to cooling portion 16 more efficiently than when only the side surface of relay portion 80a is made of metal (fourth conductor 17). If heat can be transferred from second conductor 12 on the front surface, which is the second surface of circuit board 80, to cooling portion 16, it becomes possible to narrow the widths of first conductor 11 and second conductor 12, and as a result, it becomes possible to miniaturize the power conversion device.

[0019] As described above, the power conversion device 100 according to the first embodiment includes the first conductor 11 provided on the rear surface of the circuit board 80, the second conductor 12 provided on the front surface of the circuit board 80, at least a portion of which faces the first conductor 11 via the circuit board 80, and through which a current flows in the opposite direction to that of the first conductor 11, the third conductor 13 provided on the rear surface of the circuit board 80 while maintaining an insulation distance D from the first conductor 11, and through which a current flows in the same direction as that of the second conductor 12, and at least The circuit board includes a fourth conductor 17 provided on the side wall of one or more through holes 80a and connecting the second conductor 12 and the third conductor 13, a relay portion 18a filled in the through hole 80a with a thermally conductive material, and a cooling portion 16 provided on the surface of each of the first conductor 11 and the third conductor 13 via an insulating heat transfer material 15. By arranging the first conductor opposite the second conductor and adjacent to the third conductor, inductance can be reduced not only in the opposing portions but also in the adjacent portions. Furthermore, not only the conductors on the underside of the board but also the conductors on the surface of the board can be cooled via the relay portion.

[0020] Second Embodiment In a second embodiment, a case will be described in which the configuration of the third conductor 13 in the first embodiment is also provided on the opposite side across the first conductor 11.

[0021] Fig. 4 is a schematic perspective view showing the configuration of a main circuit connection portion of a power conversion device according to embodiment 2. Fig. 5 is a cross-sectional view taken along the line AA in Fig. 4 .

[0022] As shown in Figures 4 and 5, the main circuit wiring portion in embodiment 2 has a fifth conductor 23 having the same configuration as the third conductor 13 on the opposite side of the circuit board 80 from the third conductor 13 across the first conductor 11.

[0023] The fifth conductor 23 has the same potential phase (band) as the second conductor 12, and is arranged on the back surface of the circuit board 80, which is a different layer from the second conductor 12, via the substrate 14 and the relay portion 18b provided in a through hole 80b formed in the circuit board 80. The fifth conductor 23 is arranged on the same plane as the first conductor 11, and extends on the circuit board 80 while maintaining an insulation distance D from the first conductor 11. At least one through hole 80b is formed in the circuit board 80.

[0024] The first conductor 11, the third conductor 13, and the sixth conductor 27 formed on the side wall of the relay portion 80b are configured as separate parts and are electrically connected when the circuit board 80 is molded. Unlike when a molded bus bar is used, the first conductor 11 and the second conductor 12 form parallel plates with a relatively thin substrate 14 sandwiched between them, allowing for a shorter distance between the electrodes than with a molded bus bar, which has the effect of reducing inductance. Furthermore, because the first conductor 11 and the fifth conductor 23 are arranged on the same plane, they also form parallel plates at the side portions, which is expected to further reduce inductance.

[0025] Furthermore, the above configuration can further increase the cooling efficiency of the second conductor 12 on the surface of the circuit board 80, thereby enabling further miniaturization of the power conversion device. Furthermore, since the third conductor 13 and the fifth conductor 23 are arranged so as to sandwich the first conductor 11 from the left and right, the number of parallel plate locations is increased compared to the configuration of the first embodiment, making it possible to further reduce inductance.

[0026] Other configurations of the power conversion device 100 according to the second embodiment are similar to those of the power conversion device 100 according to the first embodiment, and corresponding parts are designated by the same reference numerals and description thereof will be omitted.

[0027] As described above, the power conversion device 100 according to the second embodiment includes the following components in addition to the configuration of the first embodiment: a fifth conductor 23 sandwiching the first conductor 11 and the third conductor 13 at an insulation distance D and through which a current flows in the same direction as the second conductor 12 on the back surface of the circuit board 80; a sixth conductor 27 formed on the circuit board 80 by sandwiching the first conductor 11 between the through hole 80a and the fifth conductor 23 and provided on the side wall of the through hole 80b; and a relay portion 18b filled in the through hole 80b with a thermally conductive material. This increases the number of parallel plate locations compared to the configuration of the first embodiment, thereby further reducing inductance. Furthermore, this further improves cooling efficiency, thereby enabling a further miniaturization of the power conversion device.

[0028] Third Embodiment In a third embodiment, a case will be described in which the third conductor 13, the fifth conductor 23, and the first conductor 11 are provided over a wider area than the second conductor 12 in the first embodiment.

[0029] Fig. 6 is a cross-sectional view showing the configuration of a main circuit connection portion of a power conversion device according to embodiment 3. As shown in Fig. 6, the main circuit wiring portion in embodiment 3 is formed in a wide area on circuit board 80, beyond the area where third conductor 13 and fifth conductor 23 face second conductor 12 across circuit board 80.

[0030] With the above configuration, the third conductor 13 and the fifth conductor 23 spread over a wide area in the cooling section 16 via the insulating heat transfer material 15, improving cooling performance. As a result, the width of the second conductor 12 can be reduced, improving the degree of freedom in the mounting layout of electronic components on the surface of the circuit board 80.

[0031] Other configurations of the power conversion device 100 according to the third embodiment are similar to those of the power conversion device 100 according to the second embodiment, and corresponding parts are designated by the same reference numerals and description thereof will be omitted.

[0032] As described above, according to the power conversion device 100 of the third embodiment, the third conductor 13, the fifth conductor 23, and the first conductor 11 are formed in a wide area beyond the area facing the second conductor 12 via the circuit board 80, and therefore, in addition to the effects of the first and second embodiments, the cooling section is spread over a wide area via the insulating heat transfer material, improving cooling performance. As a result, it is possible to reduce the width of the second conductor, and the degree of freedom in mounting layout of electronic components on the surface of the circuit board is improved.

[0033] Fourth Embodiment In the first to third embodiments, the phases on the front and back sides of the circuit board are fixed, but in the fourth embodiment, a case will be described in which the phases are interchanged.

[0034] 7A to 7D are cross-sectional views showing the configuration of a main circuit connection portion of a power conversion device according to embodiment 4. 7A to 7D are cross-sectional views taken along the lines AA, BB, CC, and DD in FIG. 4, respectively. In 7A to 7D, the potentials of the conductors are indicated by (P) and (N).

[0035] As shown in Figures 7A to 7D, the main circuit wiring portion in embodiment 4 is configured such that, in the circuit board 80, the N phase (first conductor 11) on the back surface of the substrate 14 and the P phase (second conductor 12) on the front surface are interchanged from position AA to position DD, and the back surface of the substrate 14 becomes the P phase (third conductor 13 or fifth conductor 23) and the front surface becomes the N phase (seventh conductor 41).

[0036] At the DD position, the seventh conductor 41 is arranged in a pattern having the same potential as the first conductor 11 and is located on the opposite side of the substrate 14 from the first conductor 11. The eighth conductor 42 and the ninth conductor 43 are arranged in a pattern having the same potential as the seventh conductor 41 and are located on the opposite side of the substrate from the seventh conductor 41.

[0037] At the position AA shown in FIG. 7A, the P-phase (second conductor 12) is on the front surface of the circuit board 80, and the N-phase (first conductor 11) is on the cooling section 16 side on the rear surface.

[0038] At position BB shown in Figure 7B, the conductors on the front side and cooling side of the circuit board 80 are alternately arranged in the planar direction, with the P-phase and N-phase maintaining an insulation distance D from position AA. As shown in Figure 7B, the conductors are configured as follows: P-phase (second conductor 12 and fifth conductor 23) - N-phase (seventh conductor 41 and first conductor 11) - P-phase (second conductor 12 and third conductor 13). Note that although only P-phase - N-phase - P-phase is described in the fourth embodiment, it is also possible to narrow the width of the P-phase and N-phase, thereby providing multiple P-phase and N-phase configurations.

[0039] At the position CC shown in Figure 7C, the N phase (seventh conductor 41) has moved to the surface side, and the P phase (second conductor 12, fifth conductor 23, and third conductor 13) is present on the surface and below.

[0040] At the position DD shown in Figure 7D, the N phase (seventh conductor 41) spreads across the surface of the circuit board 80, and via the relay sections 18a and 18b, the N phase (eighth conductor 42 and ninth conductor 43) is also formed on the same plane as the P phase (third conductor 13 or fifth conductor 23) on the cooling section 16 side.

[0041] 7A and 7D show a state in which the P phase and the N phase are interchanged. In the fourth embodiment, a case in which the phases are interchanged once has been described, but this is not limiting. The arrangement of the P phase and the N phase on the circuit board 80 may be interchanged multiple times. In the fourth embodiment, although not shown, depending on the cooling conditions, it is possible to reduce the areas of the eighth conductor 42, the ninth conductor 43, and the relay portions 18a and 18b, thereby reducing the number of relay points.

[0042] Other configurations of the power conversion device 100 according to the fourth embodiment are similar to those of the power conversion device 100 according to the first embodiment, and corresponding parts are given the same reference numerals and description thereof will be omitted.

[0043] As described above, in the power conversion device 100 according to the fourth embodiment, the circuit board 80 is configured so that the potential phases of the conductors on the front and back sides are swapped at least once. This allows the conductors of both potential phases to be directly cooled by the cooler below the circuit board, thereby reducing the temperature difference between the conductors. Therefore, the conductors can be cooled without excessively widening the width of the conductor layers to cool the high-temperature portions of the circuit board. This allows the circuit board to be miniaturized, and as a result, the power conversion device can also be miniaturized.

[0044] Fifth Embodiment In a fifth embodiment, a case where a metal plate is mounted on the conductor surface of a circuit board 80 will be described.

[0045] Fig. 8 is a cross-sectional view showing the configuration of a main circuit connection portion of a power conversion device according to embodiment 5. As shown in Fig. 8, the main circuit wiring portion in embodiment 5 includes a first metal plate 51 on the surface of first conductor 11, third conductor 13, and relay portion 18a on the back surface of circuit board 80, and a second metal plate 52 on the surface of second conductor 12 and relay portion 18a on the front surface of circuit board 80.

[0046] The first metal plate 51 and the second metal plate 52 are mounted to the respective conductors by soldering. Note that, although the number of the first metal plate 51 and the second metal plate 52 is one each in the fifth embodiment, the present invention is not limited to this. The number and mounting positions of the plates can be selected depending on the degree to which the current is to be dispersed.

[0047] Other configurations of the power conversion device 100 according to the fifth embodiment are similar to those of the power conversion device 100 according to the first embodiment, and corresponding parts are designated by the same reference numerals and description thereof will be omitted.

[0048] In the fifth embodiment, the third conductor 13 is provided on one side of the first conductor 11, but it may also be provided on the opposite side of the first conductor 11. Fig. 9 is a cross-sectional view showing another configuration of the main circuit connection portion of the power conversion device according to the fifth embodiment. As shown in Fig. 9, the main circuit wiring portion includes a fifth conductor 23 having the same configuration as the third conductor 13 on the opposite side of the first conductor 11 from the third conductor 13 of the circuit board 80, and a first metal plate 51 and a second metal plate 52 are mounted on each conductor, as in the fifth embodiment.

[0049] In addition, in the fifth embodiment, both the first metal plate 51 and the second metal plate 52 are provided, but only one of them may be provided.

[0050] As described above, according to the power conversion device 100 of the fifth embodiment, the circuit board 80 is provided with the first metal plate 51 on the back surface thereof and / or the second metal plate 52 on the front surface thereof, so that the metal plate mounted on each conductor has the effect of increasing the cross-sectional area of ​​the current path, thereby reducing the amount of heat generated by the conductor and making it possible to reduce the temperature rise of each conductor. Furthermore, by increasing the thickness of the conductor to increase its cross-sectional area, it is possible to narrow the width of the conductor, thereby making it possible to reduce the area of ​​the circuit board and, as a result, make it possible to miniaturize the power conversion device.

[0051] Sixth Embodiment In a sixth embodiment, a case will be described in which the power conversion device 100 of the first embodiment is applied to an electric vehicle.

[0052] FIG. 10 is a diagram showing the configuration of an electric vehicle 200 using a power conversion device 100 according to a sixth embodiment of the present invention.

[0053] As shown in FIG. 6 , the electric vehicle 200 includes a power conversion device 100 according to any one of the first to fifth embodiments that converts DC power input from a battery 21 and outputs AC power, and a motor 22 (22 a, 22 b) that is driven by the AC power input from the power conversion device 100.

[0054] As described above, the electric vehicle 200 using the power conversion device 100 according to the sixth embodiment includes the power conversion device 100 according to any one of the first to fifth embodiments that converts DC power input from the battery 21 and outputs AC power, and the motor 22 (22a, 22b) that is driven by the AC power input from the power conversion device 100. Therefore, by reducing the inductance and making the power conversion device smaller, it is possible to make the electric vehicle smaller and lighter.

[0055] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0056] REFERENCE SIGNS LIST 11 first conductor, 12 second conductor, 13 third conductor, 15 insulating heat transfer material, 17 fourth conductor, 16 cooling portion, 18a, 18b relay portion, 80 circuit board, 80a, 80b through hole, 100 power conversion device.

Claims

1. a first conductor disposed on a first surface of the substrate; a second conductor provided on a second surface of the substrate, at least a portion of which faces the first conductor across the substrate, and through which a current flows in the opposite direction to that of the first conductor; a third conductor provided on the first surface of the substrate at an insulating distance from the first conductor, and through which a current flows in the same direction as the second conductor; a fourth conductor provided on a side wall of at least one through hole formed in the substrate, the fourth conductor connecting the second conductor and the third conductor; a cooling portion provided on each surface of the first conductor and the third conductor via an insulating heat transfer material; A power conversion device comprising:

2. 2. The power conversion device according to claim 1, further comprising a relay portion filled with a thermally conductive material inside the through hole.

3. a fifth conductor on a first surface of the substrate, the fifth conductor sandwiching the first conductor and the third conductor with an insulating distance therebetween, and through which a current flows in the same direction as that of the second conductor; a sixth conductor provided on a side wall of the other through hole formed in the substrate with the first conductor sandwiched between the first conductor and the through hole, the sixth conductor connecting the second conductor and the fifth conductor; 2. The power conversion device according to claim 1, further comprising:

4. 4. The power conversion device according to claim 3, further comprising a relay portion filled with a thermally conductive material inside the through hole on the other side.

5. 4. The power conversion device according to claim 3, wherein the third conductor, the fifth conductor, and the first conductor are formed in a wide area beyond an area facing the second conductor via the substrate.

6. 5. The power conversion device according to claim 4, wherein the third conductor, the fifth conductor, and the first conductor are formed in a wide area beyond an area facing the second conductor via the substrate.

7. 2. The power conversion device according to claim 1, wherein the substrate is configured such that the arrangement of potential phases of the first conductor and the second conductor is interchanged at least once.

8. 2. The power conversion device according to claim 1, further comprising: a first metal plate provided on a first surface of the substrate; and a second metal plate provided on a second surface of the substrate.

9. The power conversion device according to any one of claims 1 to 8, which converts DC power input from a battery and outputs AC power; a motor driven by AC power input from the power conversion device; An electric vehicle using a power conversion device comprising: